Method of applying sleeves to electrical connectors

ABSTRACT

Electrical connectors are post insulated by cold-forming thereon dielectric sleeves which are connected together in end-to-end strip form as a series of sleeves and this strip of sleeves is fed to a crimping station so that the leading sleeve of the strip is cold-formed over an electrical connector at the crimping station. The strip of sleeves may be made by cutting transverse slots in a plastic tube such as, for example, a tube of polyvinyl chloride.

States atent Unite Robins June 27, 1972 [54] METHOD OF APPLYING SLEEVESTO ELECTRICAL CONNECTORS [72] Inventor: Ray Mervyn Robins, Auburn, NewSouth Wales, Australia [73] Assignee: AMP Incorporated, Harrisburg, Pa.

22 Filed: Feb. 27, 1970 |2l| Appl.No.: 15,017

Related US. Application Data [62] Division of Ser. No. 680,687, Nov. 6,1967, Pat. No.

[52] US. Cl. ..264/l59, 29/630 A, 29/414, 29/417, 29/517, 264/249 [51]Int. Cl ..B29d 7/16 [58] Field ofSearch "29/203 D, 630 A, 517,417,29/414; 264/249, 159

[56] References Cited UNITED STATES PATENTS 2,288,918 7,1942 xk."i773'"1231?!i'.'Tf"I3."l 2[ LA 2,671,889 3/1954 Vickery ..29/630 A X2,839,824 6/1958 Berg ..29/4l7 2,963,775 12/1960 Chadwick ..29/630 A2,964,065 12/1960 Harolds0n.... ..264/173 X 2,974,400 3/1961 Sowa..29/63O A Primary Examiner-Charlie T. Moon Attorney-Curtis, Morris andSafford, William J. Keating, Ronald D. Grefe, Frederick W. Raring, JayL. Seitchik and John P. Vandenburg [57] ABSTRACT Electrical connectorsare post insulated by cold-forming thereon dielectric sleeves which areconnected together in end-to-end strip form as a series of sleeves andthis strip of sleeves is fed to a crimping station so that the leadingsleeve of the strip is cold-formed over an electrical connector at thecrimping station. The strip of sleeves may be made by cutting transverseslots in a plastic tube such as, for example, a tube of polyvinylchloride.

1 Claim, 8 Drawing Figures PATENTEDJUNZY r912 SHEET 5 OF 5 METHOD OFAPPLYING SLEEVES TO ELECTRICAL CONNECTORS This application is a divisionof my earlier filed case, Ser. No. 680,687, filed Nov. 6, 1967, now US.Pat. No. 3,506,41 1.

It is common practice to insulate an electrical connector which has beencrimped to the end of a wire, by crimping about the connector a sleeveof insulating material, for example polyvinyl chloride. The sleeve maybe fed to the dies of a press for crimping the sleeve to the connector,e.g. from a vibratory hopper. A disadvantage of this known method ofinsulating an electrical connector is that the sleeve tends to becomejammed or misoriented during its passage from the hopper to the dies. Afurther disadvantage of the method is that the sleeves must be appliedto the connector in loosepiece form.

According to one aspect of the invention a method of applying aninsulating sleeve to an electrical connector comprises the steps offeeding a series of insulating sleeves connected together in axialalignment to fonn a strip of such sleeves, a sleeve length at a time,towards a crimping station to dispose the leading sleeve of the strip atthe crimping station, inserting the connector into the leading sleeve,crimping the leading sleeve to the connector and shearing the leadingsleeve from the strip at the crimping station.

The strip of sleeves may readily be formed by cutting transverse slotsin a tube of synthetic plastic material, for example unplasticizedpolyvinyl chloride, the slots being spaced from one another axiallyalong the tube by the desired length of the sleeves. The slotspreferably extend perpendicularly to'the axis of the tube. The slots maybe cut by the use of a circular saw blade mounted for movement towardsand away from the tube and relative to which the tube is fed, forexample by a reciprocable feed finger and between guide plates. Sincethe flexibility of the strip is enhanced by the slots, the strip ofsleeves may readily be wound onto a storage spool and fed subsequentlyto the crimping station by the feed finger conveniently engaging theslots in the tube. A blade for shearing the leading sleeve from thestrip may be employed as a stop for limiting the entry of the connectorinto the sleeve immediately prior to the crimping operation. The feedfinger may engage in the slot between the leading and the next adjacentsleeve of the strip to act as a stop to locate the connector immediatelyprior to the crimping operation.

According to another aspect of the invention, apparatus for crimpinginsulating sleeves to electrical connectors comprises a press ram, asleeve-crimping die on the ram and a sleevecrimping anvil, the ram beingmovable towards the anvil from a top dead center position through aworking stroke to cause the die to crimp a sleeve on the anvil to aconnector inserted into the sleeve, the ram being then movable through areturn stroke, the apparatus further comprising means for feeding aseries of insulating sleeves connected together in axial alignment toform a strip of such sleeves, a sleeve length at a time towards thecrimping anvil to dispose the leading sleeve of the strip on thecrimping anvil, a shear blade mounted on the ram for shearing theleading sleeve from the strip during the working stroke of the ram and ashear blade control mechanism having a first position in which the shearblade lies between the leading sleeve on the anvil and the next adjacentsleeve in the top dead center position of the ram, so that the shearblade acts as a stop for limiting the insertion of the connector intothe leading sleeve and a second position in which the shear blade islocked to the ram during the return stroke of the ram so as to move withthe ram away from the anvil to permit a next adjacent sleeve to beadvanced onto the anvil during the return stroke of the ram.

According to a further aspect of the invention, a machine for producinga series of insulating sleeves connected together in axial alignment toform a strip of such sleeves comprises a first slide carrying arotatable circular saw blade, means on the first slide for driving thesaw blade in continuous rotation, a second slide arranged to beintermittently advanced and retracted a sleeve length at a time along apath extending transversely of the path of movement of the first slide,guide means on the second slide for receiving a length of insulatingtubing extending in the direction of movement of the second slide andintersecting the path of movement of the saw blade so that the saw bladecan form a transverse slot in the length of tubing during the advance ofthe first slide, a feed finger on the second slide for engaging thelength of tubing so that the length of tubing moves with the secondslide during the advance of the second slide, tube stop means forrestraining movement of the length of tubing with the second slideduring the retraction of the second slide, and means for synchronizingthe movements of the first and second slides so that the second slide isstationary during the advance of the first slide.

An object of the invention is to provide a strip of dielectric sleevesand to secure leading sleeves of the strip onto electrical connectors ata station for securing the sleeves onto the electrical connectors.

Another object of the invention is the provision of an apparatus forforming a tube of plastic material having suitable dielectric propertiesinto dielectic sleeves connected together in end-to-end strip form as aseries of sleeves.

A further object is to provide apparatus for securing a strip ofdielectric sleeves onto electrical connectors to provide post-insulatedelectrical connectors.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there are shown and described illustrative embodiments of theinvention; it is to be understood, however, that these embodiments arenot intended to be exhaustive nor limiting of the invention but aregiven for purposes of illustration in order that others skilled in theart may fully understand the invention and the principles thereof andthe manner of applying it in practical use so that they may modify it invarious forms, each as may be best suited to the conditions of aparticular use.

For a better understanding of the invention, reference will now be madeby way of example to the accompanying drawings, in which:

FIG. 1 is a perspective view of a machine for producing a strip ofinsulating sleeves connected together in axial alignment;

FIG. 2 is a sectional view taken on the lines 2-2 of FIG. 1, andillustrating the operation of the machine;

FIG. 3 is a fragmentary perspective view of a strip of insulatingsleeves produced by the machine of FIGS. 1 and 2;

FIG. 4 is a fragmentary perspective view of press apparatus for crimpingthe insulating sleeves to electrical connectors, the apparatus beingillustrated during the return stroke of the press ram thereof;

FIG. 5 is a longitudinal cross-sectional view of the apparatus of FIG. 4but illustrating the press ram in its top dead center position;

FIG. 6A is an elevational view taken on the lines 6A-6A of FIG. 5;

FIG. 6B is a similar view to that of FIG. 6A but with the press ram inthe position of FIG. 4; and

FIG. 7 is a view similar to FIG. 5 showing the press ram at the end ofits working stroke.

Reference will now be made to FIGS. 1 and 2. The machine comprises abase plate 2 upon which are guides 4 laterally confining a first slide 6urged rightwardly (as seen in FIG. 1) by compression springs 8 housed inbores in one end of the slide 6 and engaging a stop block 10 fixed tothe plate 2. A pneumatic motor 12 driving a cutting member such as acircular saw blade 14 is fixed to the other end of the slide 6. As shownin FIG. 2, a rod 16 extends vertically from beneath the slide 6 andthrough a slot (not shown) in the plate 2. The rod 16 carries a roller18 engaged by a cam wheel 20 driven in rotation by means, for example anelectric motor (not shown) through a shaft 22. Also mounted on the plate2 is a second slide 24 reciprocable in a direction at right-angles tothe path of movement of the slide 6 between guide plates 26. A pair ofcompression springs 28 (only one of which is shown) housed in bores inthe slide 24 engage a further stop block 30 to urge the slide 24leftwardly (as seen in FIG. 2). The slide 24 has an axial channel 32formed by guide plates 34 and 36 which are divided at right angles tothe channel 32 to provide a further channel 38 in alignment with the sawblade 14. Tiltably mounted on the plate 34 is a feed finger 40 having aworking tip 42 biased towards the base of the channel 32. Mounted on theplates 34 and 36 to the right (as seen in FIG. 1) of the saw blade 14 isa pressure pad 44 urged downwardly (as seen in FIGS. 1 and 2) by springs46 and having a rounded edge 48 by which the pad 44 can be liftedagainst the action of the springs 46. A further rod 50 depending fromthe slide 24 through a slot 52 in the plate 2 is engageable by the camwheel 20 through a further roller 54. The rods 16 and 50 have flats 56for use in screwing the rods into their respective slides.

Adjacent the block 30 is a tube stop block 58 having a through aperture60 into which extends a stop jaw 62 pivotable about a pin 64 and beingurged by a spring 66 in an anticlockwise (as seen in FIG. 2) sense ofrotation about the pin 64.

The cam wheel 20 is so arranged that the machine carries out thefollowing operating cycle when the means driving the cam wheel 20 isstarted.

The slide 6 is first advanced by the springs 8 rightwardly (as seen inFIG. 1) so that the saw blade 14, which rotates continuously, enters thechannel 38, the slide 6 being subsequently retracted by the cam wheel 20to its initial position, after which the cam wheel 20 retracts the slide24 rightwardly (as seen in FIG. 1) against the action of the springs 28,by which the slide 24 is then advanced towards its initial position.

In operation, a length of thermoplastic tubing T, e.g. of unplasticizedpolyvinyl chloride is fed through the aperture 60 of the block 58 fromthe left-hand (as seen in FIG. 2) end of the aperture 60 to drive thejaw 62 in a clockwise (as seen in FIG. 2) sense of rotation against theaction of the spring 66, the length of tubing T being passed through thechannel 32 beneath the pressure pad 44 and feed finger 40, as shown inFIG. 2. The pad 44 and finger 40 are lifted manually to permit passageof the length of tubing T through the channel 32 and are subsequentlyreleased.

The means driving the cam wheel 20 is now started, eg by actuating apedal switch (not shown) so that the slide 6 is advanced to cause thesaw blade 14 to enter the channel 38 so as to cut a transverse slot S inthe length of tubing T to leave a slug SI. of tube material at the baseof the slot S. The slide 6 is then retracted by the cam wheel 20 and theslide 24 is moved by the cam wheel 20 rightwardly (as seen in FIG. 1) sothat the working tip 42 of the feed finger 40 lies on the length oftubing T slightly to the right (as seen in FIG. 2) of the slot S thathas just been formed by the saw blade 14. The action of the jaw 62prevents the length of tubing T from being retracted with the slide 24.As the slide 24 is now advanced under the action of the springs 28, thetip 42 of the feed finger 40 engages in the newly formed slot S so thatthe feed finger 40 drives the length of tubing T leftwardly (as seen inFIG. 2) after which the saw blade 14 is again advanced to slot thelength of tubing T at a position back from the slot S first formed, asthe working cycle of the machine is repeated.

It will be apparent that the machine just described produces acontinuous strip ST of insulating sleeves SV (see FIG. 3) connectedtogether in axial alignment, each sleeve SV being connected to the nextadjacent sleeve SV by a slug SL of the material of the length of tubingT.

Apparatus for crimping the sleeves SV to electrical connectors will nowbe described with reference to FIGS. 4 to 7. The apparatus comprises apress ram 70 (only part of which is shown) arranged to be driven invertical reciprocation through a stroke of predetermined length by anelectric motor (not shown) through a toggle linkage (not shown). Theelectric motor is actuable by depressing a pedal switch (not shown)through a one-shot clutch (not shown) so that upon actuation of thepedal switch the ram 70 is automatically driven through a downward orworking stroke and an upward or return stroke after which the ram 70remains stationary in its top dead center position until the pedalswitch is next depressed.

The ram 70 carries sleeve crimping dies 72 and 74 having workingsurfaces 73 and 75, and a sleeve shear blade holder 76 in which ismounted a shear blade 78 slidably arranged between the holder 76 and acover plate 80 having a central downwardly opening slot 82. The shearblade 78 has a shearing edge 84 bridging a pair of spaced depending legs86 of the shear blade 78. A pin 88 extending at right-angles from theshear blade 78 projects through the slot 82 in the cover plate 80leftwardly (as seen in FIGS. 5 and 7). A two-armed latch member 90 ispivotally mounted on a pin 92 on a projection 94 of the shear bladeholder 76 and is urged in a clockwise (as seen in FIGS. 6A and 6B) senseof rotation about the pin 92 by a spring 96 attached at one end to themember 90 and at the other to the cover plate 80 so that the left-hand(as seen in FIGS. 6A and 6B) arm of the member 90 bears against the pin88. On the opposite side of the pin 92 to the spring 96, the member 90carries a pin 97 which projects laterally from the member 90. A stop pin98 projects from a plate 100 which is mounted, for adjustment in a leftto right (as seen in FIGS. 6A and 6B) direction on a portion 101 of theframe of the apparatus which frame is otherwise not shown. The shearblade holder 76 and the member 90 thereon are thus movable with the ram70 relative to the stop pin 98.

The apparatus further comprises a press bed portion including a mountingblock 102 carrying a strip feed plate 104 on which are strip guideplates 106 defining a strip feed channel 108 (FIG. 4). Also mounted onthe plate 104 is a pressure pad 110 urged downwardly (as seen in FIG. 4)by springs 112. A strip feed finger 114 having a working tip 116 isurged downwardly (as seen in FIGS. 4, 5 and 7) by a spring (not shown),the feed finger 114 being arranged to be driven in left-to-right (asseen in FIGS. 4, 5 and 7) reciprocating motion by means (not shown) forexample a piston and cylinder device.

Also mounted on the block 102 are sleeve crimping anvils 1 18 and 120having working surfaces 122 and 124 respectively, in alignment with theworking surfaces 73 and 75 respectively, of the dies 72 and 74. Adjacentthe anvil 120 is a first shear plate 126 spaced from a second shearplate 128 by separator plates 130 (only one of which is shown) to definea space 132 into which the legs 86 of the shear blade 78 extend.

The apparatus has a rotary storage spool (not shown) mounted on theframe of the apparatus or upon a separate stand (not shown) about whicha spool or strip ST of sleeves SV produced by the machine of FIGS. 1 and2 is wound. Also, as the strip of sleeves is being made by the machineof FIGS. 1 and 2, the strip can be simultaneously fed into the crimpingapparatus of FIGS. 4-7.

With the ram 70 in its top dead center position as shown in FIG. 5, theend of the strip ST on the spool is laid into the channel 108 beneaththe pad 110 which is raised manually to permit this. The end of thestrip ST is further led beneath the working tip 116 of the feed finger114 which is also raised manually to allow passage of the strip. The padI 10 and finger 114 are then released so as to be returned to theposition of FIG. 5 under the action of their springs. The shear blade 78is now raised manually from the position of FIG. 6A to that of FIG. 6Band the end of the strip ST is passed beneath the edge 84 of the blade78 so that the leading sleeve SV of the strip rests upon the plate 126and upon the working surfaces 122 and 124 of the anvils as shown in FIG.5. The shear blade 78 is then released and falls back so as to extendinto the slot S between the leading sleeve SV and the next adjacentsleeve SV, the edge 84 of the blade 78 resting upon the slug SL betweenthese sleeves. The apparatus is now ready for operation.

An electrical connector C for example an electrical tab receptacle,already crimped to a wire W is inserted into the leading sleeve SV untilthe connector C engages the shear plate 78 which as aforesaid extendsinto the slot S between the sleeve SV and the next adjacent sleeve SV.The connector is accordingly precisely positioned axially within thesleeve SV.

Upon actuation of the pedal switch the ram 70 is driven through aworking stroke so that the sleeve SV is crimped about the connector Cbetween the working surfaces 73 and 75 of the crimping dies 72 and 74and the working surfaces 122 and 124 of the anvils 118 and 120. Duringthe working stroke, the shear blade holder 76 descends with the ram 70so that the holder 76 moves downwardly relative to the shear blade 78causing the shear blade 78 to bottom against the holder 76 whereby theshear blade 78 is driven downwardly with the holder 76 to cause theshearing edge 84 of the blade 78 to shear the slug SL from between theleading sleeve SV and the next adjacent sleeve SV in co-operation withthe shear plates 126 and 128. The edge 84 thus enters the space 132 asshown in FIG. 7.

The ram 70 now automatically carries out its return stroke under theaction of the one-shot clutch. As the ram 70 rises, the shear bladeholder 76 rising with the ram 70, the latch member 90 urges, under theaction of its spring 96, the pin 88 on the shear blade 78 upwardly (asseen in FIG. 68) so that the shear blade 78 is retained in its bottomedposition against the holder 76 and thus rises with the holder 76 so thatthe edge 84 of the shear blade 78 is raised above the next adjacentsleeve SV and is thus positioned as shown in FIGS. 4 and 6B. The pin 97on the latch member 90 engages a microswitch (not shown) to actuate thedriving means for the feed finger 114 so that the feed finger carriesout a working or leftward (as seen in FlG. 5) stroke to advance the nextadjacent sleeve SV under the edge 84 and between the legs 86 to push thesleeve SV off the anvils and to take up the position originally occupiedby the sleeve SV. As the ram 70 continues its upward travel, the latchmember 90 strikes the stop pin 98 so that the latch member 90 is rotatedfrom the position of FIG. 6B to that of FIG. 6A against the action ofthe spring 96 to permit the shear blade 78 to fall back to the positionof FIGS.

5 and 6A. The stop 91 engages a further micro-switch (not shown),causing the feed finger 114 to be retracted to its initial position asshown in FIG. 5. The microswitches are arranged to be inoperative duringthe working stroke of the ram 70. The parts of the apparatus are nowagain positioned as shown in FIGS. 5 and 6A so that the apparatus isready for a further cycle of operation.

As an alternative to employing the shear blade as a stop for limitingthe insertion of the connector into the sleeve, the working tip of thefeed finger may be employed as the stop. In this case the shear blade isfixed relative to the ram and in the top dead center position of theram, the shearing edge of the shear blade lies well above the strip ofsleeves. The feed finger is arranged to assume its fully advancedposition in the top dead center position of the ram so that a connectorinserted into the leading sleeve engages the working tip of the feedfinger, when fully inserted into the leading sleeve. The feed finger isretracted during the working stroke of the ram.

It will, therefore, be appreciated that the aforementioned and otherdesirable objects have been achieved; however, it should be emphasizedthat the particular embodiments of the invention, which are shown anddescribed herein, are intended as merely illustrative and not asrestrictive of the invention.

The invention is claimed in accordance with the following:

1. A method of applying insulating sleeves to electrical connectorscomprising the steps of feeding a tube of plastic material into acutting area, cutting said tube at predetermined lengths thereby forminga series of insulating sleeves connected together in an end-to-endstrip, feeding the strip of insulating sleeves towards an applyingstation so that a sleeve at a time is placed at said applying station,inserting an electrical connector into a leading sleeve of said stripwhich is positioned at said applying station, securing the leadingsleeve to the electrical connector, and shearing the leading sleeve fromthe strip adjacent said apply ing tation

1. A method of applying insulating sleeves to electrical connectors comprising the steps of feeding a tube of plastic material into a cutting area, cutting said tube at predetermined lengths thereby forming a series of insulating sleeves connected together in an end-to-end strip, feeding the strip of insulating sleeves towards an applying station so that a sleeve at a time is placed at said applying station, inserting an electrical connector into a leading sleeve of said strip which is positioned at said applying station, securing the leading sleeve to the electrical connector, and shearing the leading sleeve from the strip adjacent said applying station. 